winkler



Patented Sept. 9, 1952 UNITED srAras PATENT OFFICE BendixAviationCorporation, South Bend, Ind., a corporation of. Delaware 1.

Application March '7, 1950,*Serial No. 1f1 8,1'98

The present invention relates to carburetors for internal combustionengines, and more particularly to carburetorsof the multiple stage typefor automotive engines.

In the operation of a multiple stage carburetor having primary andsecondary induction systems, only the primary system is employed atlower engine speeds so that relatively high air velocities will bemaintained in the induction passage to give agreater effectivesuctionfor fueldelivcry and thus a more positive control over fuel metering anddistribution during the period, of-

relatively low airflow. Withthe acceleration of the engine to the higherspeed ranges, the secondary induction system becomes operative toincrease the volume offuel-air delivery sufficient- 1y tobbtain maximumpower output and speed of the engine. The present invention is 'principally concerned with a mechanism for control: ling, themsecondaryinduction system in response to throttle position in the primaryinduction sys-. tem and touthe temperature of the ,engine, o'ne of theobjects'of the invention being to provide a temperature responsive meansfor rendering the control mechanism ineffective to actuate the secondarysystem until the engine hasvreached a predetermined temperature. l n

Anotherobject of the invention is toprovide a carburetor having aprimary and a'secondary induction system wherein the'secondary system iscontrolled in response to throttle position in the primary system andisbrought into operation gradually as the, engine accelerates.

Another object of the invention is to provide, in a multiple stagecarburetor havingamechanism controlled in accordance with the movementof throttle valve in the primary system for controlling the throttlevalve of the secondary system, a temperature responsive means'for posi--tively; preventing the secondary throttle valve fromioperatin'g whilethe engine is cold.

Another object-is to provide in a multiple stage Claims. (01.123-127).

carburetor of the aforesaid type a mechanism primary system, wherein thesecondarysystem remainsinefiective while the choking device is effectivel t l :Additional objects and advantages: will become a :-:*2 p apparentfrom the following description and accompanying drawings, wherein:

. Figure l-is a side elevation of a multiple stage carburetor showingcertain elements of thecontrol mechanism for the secondary inductionsystem in cross-section; 1

Figure 2 is a partial side elevation of a multiple stage carburetorshowingportions of the control mechanism of the secondary inductionsystem in cross section as in Figure 1, but in a different operativeposition; and

Figured is a view of certain levers forminga part i of l the controlmechanism.

Referring more'specifically to the drawings, and to Figure l inparticular, a multiple stage carburetor" generally designated by numeralIn is shown mounted on an intake manifold I2 of'an internal combustionengine (not shown) and contains a-pr'imaryinductionsystem |4Aand a secondary induction system I4B,in'cluding induction passages IBA'and 18B,throttles 20A and 20B and main discharge jets 22A and 223, respectively.The two systems are provided with separate idle systems, fuel inletvalves and float chambers and are adapted to discharge the fuel-airmixture directly into intake manifold 12. A single accelerating pump(not shown), which may be either a mechanical or a vacuum type pump, isadapted to discharge into the primary induction system as the primarythrottle is opened. In the present carburetor only the primary inductionsystem is controlled by a choke valve 24, preferably of the unbalancedtype, mounted in the airinlet of the induction passage 18A on a shaft26, said choke valve being controlled either by a manual means or by anautomatic choking device having a thermostatic element and a vacuumactuated means.

The throttle valve 20A. of the primary inducetion system is manuallyactuated by the operator through lever 30 mounted on one end of throttleshaft 32 and is regulated in the degree of closing by a stop 'screw' 34on said lever and a fast idle cam 36 controlled through a linkage (shownin part at 31) by a choke control mechanism (not shown) The throttlevalve 20B of the secondary induction passage is controlled by theprimary throttle valve through a linkage consisting of a lever3Brotatably mounted on one endof shaft 32, a lever 40 rigidly mounted-onone end of throttle shaft 42 of the secondary throttle valve 20B and arod 44 interconnecting levers 3B and 40, said rod being pivotallyconnected to theiree end'o'f'lever 38 and to lever 40 by a trunnion.

through which saidrod is adapted to slide. The

3 force tending to open the secondary throttle valve as the primarythrottle valve is opened is transmitted from rod 44 through a coilspring 48 mounted on said rod and reacting between a fixed collar 58 andtrunnion 46. Lever 38 is actuated in the direction to open the secondarythrottle valve by lever 30 through a one-way connection consisting of a'11'1g52fi0n lever '38 adapted to be engaged by lever 30 as said latterlever is moved in the opening direction. The position of lever 38 inrelation to lever 30 is such that the primary throttle valve must bemoved to partially opened position before the secondary throttle valveis unobstructed by said thermostat. Spring 48 which forms a yieldableconnection between levers 38 and 40 permits the primary throttle valveto be moved to its wide open position while the secondary throttle valveis held closed by thermostatic element 10.

In the operation of the present carburetor, starting with the enginecold, the choke valve 24 will beclosed and the secondary throttle valvewill be held in its latched position by the finger 12 of thermostat l0hooked over the end of lever 73. During the warm-up period, the primaryinduction system is the sole source of fuel-air mixmoved toward openposition, though the movement of the primary throttle valve after thesecondary throttle valve has started to open is sufficient to fully openthe secondary throttle valve. An arm 54 on lever is adapted to engagelever 38 as the primary throttle valve is movedtoward closed positionand to positively move said lever in the direction to close thesecondary throttle .valve. The effective length of rod 44 intransmitting the closing movement of lever 38 to lever may be adjusted bmoving nuts '55 and 56 upwardly or downwardly on rod 44, nut 56 beingused to lock nut in place after an adjustment has been made;

Lever All through arm 58 is connected to a dashpot 60 to retard theopening movement of the secondary throttle valve untilthe engine has hadsufiicient time to respond to the-opening of the primary throttle valve.This arrangement gives a higher air velocity for engine acceleration anda larger volume of fuel-air mixture for high power output and-speedafter acceleration. The dashpot, which maybe built integrally with thecarburetor, using'fuel from thegfuel bowl as the hydraulic fluid, isshown mounted on the side of the carburetor as aself-contained unit,consisting of cylinder 62 and-a pistonfimconnected' to arm 58 by a rod68. ;A-calibrated orificefiB is provided in piston 64 to permit thefluid beneath the piston to pass slow-ly'to the spaceabove' the pistonas the secondary throttle valve is urged to its open position by spring48 after the primary throttle valve has been opened sufliciently tocause lever 30 to engage lug 52 and move lever 38 in the clockwisedirection. Apassage having a check valve GQthereinis provided in pistonE ite permit the rapid return of the secondary throttle valve to itsclosed position. r

- v To prevent the secondarythrottle valve from opening before theengine becomes warm, a bimetallic thermostatic element having a finger'IZiOr'engaging a lever'i3 is provided to positively hold the throttlevalve 26B closed while the engine is cold, lever 13 being rigidlysecured to shaft 42 and adapted to rotate in unison with lever 45 andarm 58. The thermostat is disposed in a housing 14 and secured to thewall thereof by a rivet 16 or the like. Heated air from a stove or thelike (not shown) adjacent the exhaust manifold of the engine is drawn byintake manifold vacuum through tube 18 around thermostat ill in thehousing and thence through tube 88 to the intake manifold l2. When theengine is cold, the free arm of the thermostat assumes the posi tionshown in Figure l with finger 12 hooked over one end of lever 13, saidend being beveled to permit the throttle valve 203 to close after thethermostat has moved to the position shown in Figure 1. As the enginebecomes warm, the free arm of the thermostat moves to the right, asshown in Eigure 2 sufficiently to free lever 13 and permit saidlever andthrottle valve -20B touotate i ture for the engine at part and wide openthrottle operationsthough during idling the idling systerns of'both theprimary and secondary induction systems are in operation regardless oftemperature. As the engine becomes warm, the heated air drawn from thestove around the exhaust manifold passes through housing 14, heatingthermostat 10 and causing it to move in the direction to release lever13. The choke valve, which is preferably of the automatic type, is alsogradually opened as the engine becomes warm. After the engine has becomefully warm and thermostat 10 isfully withdrawn from lever 13, theopening movement of the primary throttle valve beyond the point at whichlever 30 engages lug 52 of lever 38 moves rod 44 downwardly, compressingspring 48, which in turn urges lever 40 in the direction to open thesecondary throttle valve 20B. The opening movement of the throttle valve2GB is retarded by dashpot 60 so that the air now through the primaryinduction passage will have time to increase to the amount correspondingsubstantially to the increased throttle opening, beforethe secondarysystem becomes effective. When the primary throttle valve is movedtoward, closed position, arm 54 engages lever38 and through rod- 44 andlever 40 positively moves secondary throttle valve 203 toward closedposition.

Many modifications may be made in the present device without departingfrom the scope of the present invention, for example; the thermostaticmeans for holding throttle valve20B in its closed positionmay be of anyother suitable. type than that shown in the drawings, or said throttlevalve may be controlled by the thermostat of the automatic choke.Further, while only one induction passage for each of the two systems isshown, each system may include a plurality of induction passagescontaining throttle valves actuated by a control mechanism such as theone shown in the drawin'gsi- Further modifications may be made to suitrequirements. i i

l. A carburetor for an internal combustion engine comprising a primaryinduction passage having a throttle therein, a secondaryinductionpassage having a throttle therein, a means for positively opening saidprimary throttle, a linkage connecting said throttles and having ayieldable connection therein, and a dashpot'for retarding the openingmovement of said secondary throttle to permit the primary throttle toopen fully before the secondary throttle has opened fully.

2. A carburetor for an internal combustion engine comprising aprimaryinduction passage having a throttle therein, a secondary inductionpassage having a throttle therein, a linkage COI'lHECt-v ing saidthrottles and having a yieldable connection thereima dashpot forretarding the opening movement of said secondary throttle-to permit theprimary throttle to open before the secondary throttle is opened, and athermostatic means for holding said secondary throttle closed when theengine is cold.

8. A carburetor for an internal combustion engine comprising a primaryinduction passage having a throttle therein, a manually actuated meansfor positively opening said primary throttle, a secondary inductionpassage having a throttle therein, a linkage connecting said throttlesand having a yieldable means therein and including a lost motionconnection to permit the primary throttle to open to a predeterminedposition before the secondary throttle is opened, and a dashpot forretarding the opening movement of said secondary throttle.

4. A carburetor for an internal combustion engine comprising a primaryinduction passage having a throttle therein adapted to be manuallyactuated, a secondary induction passage having a throttle therein, alinkage connecting said throttles and having a yieldable means thereinand including a lost motion connection to permit the primary throttle toopen to a predetermined position before the secondary throttle isopened, a dashpot for retarding the opening movement of said secondarythrottle, and a thermostatic means for positively holding said secondarythrottle in closed position when the engine is cold.

5. A carburetor for an internal combustion engine comprising a primaryinduction passage having a throttle therein, a lever for positivelyactuating said throttle, and a secondary induc tion passage having athrottle therein, a linkage including a means adapted to yieldably urgesaid secondary throttle in the opening direction as the primary throttleis opened, a lost motion connection between said linkage and saidprimary throttle lever, and a means for retarding the opening movementof said secondary throttle.

6. A carburetor for an internal combustion engine comprising a primaryinduction passage having a throttle therein, a lever for positivelyactuating said throttle, a secondary induction passage having a throttletherein, a linkage including a means adapted to yieldably urge saidsecondary throttle in the opening direction as the primary throttle isopened and to positively close the secondary throttle as the primarythrottle is closed, a lost motion connection between said linkage andsaid primary throttle lever, and a dashpot for retarding the openingmovement of said secondary throttle. V

7. A carburetor for an internal combustion engine comprising a primaryinduction passage having a throttle therein, a lever for actuating saidthrottle, a secondary induction passage having a throttle therein, alinkage including a means adapted to yieldably urge said secondarythrottle in the opening direction as the primary throttle is opened, alost motion connection between said linkage and said primary throttlelever, a means for retarding the opening movement of said secondarythrottle, and a means responsive to engine temperature for holding saidsecondary throttle in closed position when the engine is cold.

8. A carburetor for an internal combustion engine comprising a primaryinduction passage having a throttle and a choke therein, a lever foractuating said throttle, a secondary induction passage having a throttletherein, a linkage including a means adapted to yieldably urge saidsecondary throttle in the opening direction as the primary throttle isopened and to positively close the secondary throttle as the primarythrottle is closed, a lost motion connection between said linkage andsaid primary throttle lever, a dashpot for retarding the openingmovement of said secondary throttle, and a means responsive toenginetemperature for positively holding said secondary throttle closedwhen the choke in the primary induction passage is efiective to restrictthe flow of air therethrough.

9. A carburetor for an internal combustion engine comprising a primaryinduction passage having a throttle therein, a means for positivelyopening said primary throttle, a secondary induction passage having athrottle therein, a linkage connecting said throttles and having ayieldable connection therein, and a means for retarding the openingmovement of said second ary throttle.

10. A carburetor for an internal combustion engine comprising a primaryinduction passage having a throttle therein, a secondary inductionpassage having a throttle therein, a linkage connecting said throttlesand having a yieldable connection therein, a means for retarding theopening movement of said secondary throttle,

and a means responsive to engine temperature for holding said secondarythrottle valve closed when the engine is cold.

ALBERT H. WINKLEIR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Winkler Sept. 7, 1943

